Detectives Against The Dark Arts
by eclecticist
Summary: When Sherlock decides to investigate the curse that surrounds the Defense Against The Dark Arts post at Hogwarts, he finds a temporary and unexpected distraction in the Quidditch teacher, a certain John H Watson. Inspired by tumblr.
1. Chapter 1

Before John Watson closed his eyes his last image was that of the empty seat in front of him, and then his head tilted gently to the side so that it was leaning against the window of the train, and he fell asleep.

John never woke up gently though, his nightmares forbid him from that. Instead he woke up with a start, breathing heavily, trying to separate himself from his dreams.

And the first image that greeted John this time was that of a man. A very curious looking one indeed.

The man's posture was relaxed, but straight. His hands were in front of him, his fingertips touching gently. His eyes were closed.

John had a feeling he wasn't asleep though.

The man hadn't changed into his robes yet. He was in a large black coat, a blue scarf lay discarded to his side. His dark curly hair was ruffled, and fell over his forehead.

John realized how rude it was of him to be staring only when the man's eyes shot open, suddenly.

"Um." Said John.

But the man's eyes were quite vacant, almost dreamy. And he didn't even seem to acknowledge John Watson's presence. John wondered briefly if the man opposite him was on narcotics.

And then something snapped in the man's eyes and he was in his feet so suddenly that John flinched.

"Care to introduce yourself?" John said, frowning slightly.

Sherlock looked down at him. His eyes were green.

"John Watson, I assume." He said, his lips curving upward slightly. "I suggest you give your brother that phone call you promised, we've almost reached our destination."

Sherlock Holmes opened the compartment door and disappeared, his coat flapping behind him.

John took his cell phone out of his pocket. Five messages from Harry. Shit, he had promised to call her as they were reaching. John glanced at the closed compartment door and wondered if the new Defense Against The Dark Arts teacher could read minds.


	2. Chapter 2

John was saying goodbye to Harry when the train slowed down and Sherlock made his reappearance, this time with Mike Stamford.

"Uh Harry, I'll have to talk to you later then, we're reaching." He said hurriedly.

"Cute girl enter the compartment?" John could hear the smile in his sister's voice. "I'll leave you to it then."

"Shut up Harriet." John replied. "Be good, then." And he slipped the phone into a pocket of his cloak.

"_Harriet_," the man said, sounding displeased. "Your sister then?"

"I'm sorry, I'm not quite sure how you know that." John said. And then, to Stamford, "Hello Mike."

"John," Mike smiled. "I see Sherlock's already begun his little analysis."

"Sorry, what?"

"Show him then, Sherlock." Mike said.

Sherlock took a seat. John noted he still hadn't changed into his robes.

"As much as I'd like to flaunt, to impress your friend here, my mind is rather pre-occupied at the moment." He said smoothly.

"Sherlock Holmes, I've read that name before." Said John.

"Yes well, the Daily Prophet can't get enough of me," Sherlock said, managing to sound conceited and disinterested at the same time.

"No, not that." John said. "I read one of your articles. The Magic of Deduction, was it?"

Sherlock looked up sharply.

"What was your opinion?"

John felt slightly disconcerted by the man's piercing gaze, but he replied honestly. "Seemed a bit fantastical. What was it you said? 'There is no magic in deduction'? You claimed muggles are capable of it."

"Depends on the muggle." Sherlock said. "But I require no magic for what I do. I am one of the few wizards not dependent on magic."

John scoffed slightly.

Mike raised his eyebrow at Sherlock. "You can't possibly pass this opportunity." He said.

Sherlock smiled coldly.

He fished his wand out of one of his pockets and handed it to Mike.

"As you can see, Mike here is holding my wand. Nonetheless, I shall proceed to perform what is commonly mistaken as magic."

He looked John up and down. John looked back at him, refusing to waver.

"You were a previously an auror, sent to work in Afghanistan or Iraq, clearly. You evidently have a sister, Harriet, forgive my earlier presumption that she was a brother. You secretly share my disdain for magic, and are, in fact, apprehensive of holding a wand, which is visible by the slight tremor in your left hand when you are holding one, which your therapist believed to be a sign of post-traumatic stress. You quite recently quit your job as an auror, so my assumption is that you were hit by one of the unforgivable curses, possibly… The cruciatus curse?"

There was silence.

John picked up his suitcase, silently. His hand had stopped trembling. He vaguely heard Mike calling his name. He squeezed his eyes shut but that made things worse. All he could see now was the flash of light that he associated with pain.

Unbearable pain.

He had to get out.

He fumbled with the compartment door, got out, and ran.


	3. Chapter 3

John stood outside at the train, looking at the spiral of towers and turrets that compromised Hogwarts. The lake was silent and inky under the night sky. He wondered briefly if the squid would greet them or was too busy napping. He seemed to be wondering briefly about many things: squids, the man in the train, cruciatus curses, the man in the train, blinding pain and pleas of mercy and or course, the man in the train.

His thoughts were interrupted by voices behind him, growing louder as they approached him.

"Frankly, I don't understand what McGonagall was thinking when she hired you." It was a nasal voice, belonging to a man.

"Frankly, Anderson, I don't think you understand very much at all."

Of course.

The man in the train.

"So witty, Sherlock." Anderson's voice dripped with sarcasm. So that was his name; Sherlock. It was unsusual.

Then a female's voice, "Tell me Sherlock; how does a threstral look?"

"What are you implying?" Sherlock's voice was soft, but laced with condescension.

"Well, judging by the number of dead bodies you seem to enjoy hanging around, I'd assume you'd have begun seeing them by five."

"I wonder if he talks to them, like that skull he carries around?" sneered Anderson. "Considering his lack of friends, I'm not surprised."

"Enough!"

The trio's eyes widened as John spun around. He was surprised at the menace in his own voice.

"You're bloody grown-ups." He said. "Can't you give a guy a break?"

Anderson narrowed his eyes at John. "Come on, Sally." He said. The think dark woman looked at John with his eyebrows raised, "Did Sherlock make a friend after all? Are you a psycho too, then?"

John wondered for a second if his outburst had been wise.  
"I'm not a friend, but that doesn't mean I can't support him, with you all ganging up on him like high school students."

"Comparing them to high school students would be an insult to high school students." Sherlock spoke up. John noted his voice again. It was calm, but with a slight edge to it, the kind that demanded attention. He had been looking at John with an unidentifiable glint in his eyes. "Nursery children seem more apt."

Anderson seemed to have run out of retorts, and turned his back on them with a dramatic swish of his robe. Sally followed a second later.

John, suddenly feeling slightly embarrassed, stepped into one of the carriages being drawn by the threstrals. Sherlock stepped in too and sat opposite to him.

"I can see them too, you know." John said quietly, indicating the large grey threstral pulling them along with a slight tilt of his head.

"I had assumed." Sherlock replied.

"Oh yeah, about that… um." John said awkwardly. "How?"

Sherlock shifted his focus from John's face, which relaxed him slightly. He felt like he was being scrutinized. "How what?"

"How do you know all that?"

"Quite obvious, considering you were an Auror."

"How did you know I was an Auror?" John raised an eyebrow. "How do you know practically everything about me?"

Sherlock took a deep breath, his gaze still focused on some point behind John's shoulder.

"Well you have a wand that is willow, 12 3/4", quite rigid, dragon heartstring- a specialty of Gregorwin, native to Iran, but he does ship his products to Afghanistan- hence creating my confusion as to where you were previously located. Your haircut, the way you hold yourself says Auror- a fact confirmed by the observation that you had been abroad- considering the tense situation between the Government and the Death Eaters in Iran. Naturally, an auror was sent.

Then there was your suitcase- it had the label Harry Watson on it. It couldn't have been your name since moments later you received a call from a person of the same name, proving the suitcase wasn't your own but handed down to you from your brother- sorry, sister. The number of missed calls intersecting with the time of arrival of the train led me to believe that you had forgotten to call this Harry, something you had promised to do on arrival."

He had said this all with barely a pause between his sentences. John just stared at him in awe.

Sherlock glanced at him for a moment.

"That was… amazing." John said.

Sherlock's impassive face gave away a momentary expression of surprise. "Do you think so?"

"Of course it was. It was extraordinary… it was quite extraordinary."

Sherlock blinked.

"That's not what people normally say."

"What do people normally say?"

"Silencio."


End file.
